An image forming apparatus includes an image bearing member; an electrostatic image forming unit for forming an electrostatic image on said image bearing member, the electrostatic image forming unit including a flexible charge member for electrically charging the image bearing member, the charge member forming a nip between the image bearing member and itself and is supplied with an oscillating voltage, wherein electroconductive particles are provided in the nip; and a developing unit for developing an electrostatic image formed on the image bearing member with a developer, the developing unit being capable of a residual developer on the image bearing member, wherein a frequency f (cycle/sec) of the oscillating voltage and a peripheral speed v (mm/sec) of the image bearing member satisfy |f/v|≧12 (cycle/mm).